Systemic injection of chemotherapy agents for treating cancer can cause severe side effects for the patient, as well as being a relatively inefficient use of expensive and highly toxic drugs. The area of targeted drug delivery in which drugs are delivered utilizing a specialized carrier directly to the cancerous tumor via immuno-recognition has gained much interest in recent years. Such an approach reduces the side effects of systemic injection and also provides a localized, high-concentration treatment directly to the cancer. Our group at the University of Leeds (Leeds, UK) is developing therapeutic microbubbles that double as both agents for contrast-enhanced ultrasound imaging and drug-delivery vehicles that are targeted to specific cancer cell receptors. Ultimately, a large amplitude sound wave will be used to destroy the bubbles and trigger release of the drug at the targeted tumor. Theranostic microbubbles are a simple and versatile drug-delivery technique that could potentially improve cancer treatment, both in terms of patient experience and overall drug efficiency. Importantly, they offer new ways of delivering hydrophobic drugs, which have traditionally been difficult to deliver efficiently.